Thermoelectric switch



March 10, 1931. H. JONES 1,795,400

THERMOELECTRIC SWITCH Filed April 2, 1924 IN VEN TOR WITNESSES 'H/ L'TON IR A Jozvcs Mfuzam 1' BY A v W 6 A TTORNE YS Patented Mar. 10, 1931 PATENT OFFICE HILTON IRA JONES, OI WIIME'ITE, ILLINOIS rnnnmonnncrnrc swrrcn Application filed April 2, 1924. Serial No. 708,732.

The present invention relates to new and useful improvements in automatic switch breakers and closers, and it pertains more particularly to such devices that are therlmally controlled.

It is one of the primary objects of the present invention toprovide athermally controlled circuit breaker in which the contacts at the breaking point are opened and closed suddenly with a minimum amount of arcing.

It is a further object of the invention to construct a device of this character in such a manner that the expansible media employed operate to produce an end thrust rather than a lateral thrust, thus giving sufficient power to operate the opening and closing of the circuit breaking contacts with sufficient speed to prevent undue arcing at this point.

It is a further object of the invention to provide a relatively small device of this character and yet produce therein a high degree of efiiciency.

With the above and other objects in View, reference is had to the accompanying drawings, in which Figure 1 is a view in elevation, partly in section, of a device constructed in accordance with the present invention;

Fig. 2 is a diagrammatic view showing the use of a condenser in the circuit to reduce arcing or sparking at the breaking point of the circuit;

Fig. 3 is a top element.

Referring more particularly to the drawings, the device comprises two end frame members 5 and 6. The end frame member 5 has an angular arm 7 projecting from its upper face, and mounted in said arm and having screw threaded engagement there with there is an adjusting screw 8. The lower frame member 6 has an angular extension 9 terminating in an angular arm 10, the

end of which is formed with a shoulder 11.

Mounted in the frame member 5 and 6,

there being openings 12 for this purpose,

there is a plurality of expansible elements 14,

said expansible elements being free to move within" their respective openings 12. These expansible elements have a high coefficient of plan view of the breaking expansion, and interposed with respect to these elements there are pillars or posts 15 of a relatively low coefficient of expansion,

such pillars or posts serving to maintain the frame members 5 and 6 in position with respect to each other. One end of the outer member 14 is adapted for engagement with the adjusting screw 8 heretofore mentioned and the other end engages one end of a T- shaped rocking lever 16 pivotally mounted upon the frame 6. The other end'of the rockin lever 16 is engaged with the lower end 0 .the central expansible member 14, and the upper end of said central expansible member 14 is engaged with one end of a substantially T-shaped rocking lever 17 pivotally connected to the frame member 5, the other end of the rocking lever 17 engages the upper end of the other expansible member 14.

Secured to the lower end of one of the pillars or posts 15, as by means of a screw 20 or the like, there is a bracket 21, and carried by such bracket there is an extension 22 of suitable insulating material, which extension rests upon the shoulder 11 heretofore mentioned.

Carried by the insulating material 22, there is a binding post 23, and such binding post is provided on its free end with a contact member 24. A conductor 25 is suitably 0 secured to the binding post 23.

The reference numeral 26 designates a suitable insulating washer and carried by said washer there is a spring metal plate 27 provided with a stamped projection 28. This 85 stamped projection 28 is adapted for engagement with the lower end of the last-mentioned expansible member 14, as shown in section in Fig. 1. Connected to this plate there is a conductor 28, and this plate is provided 90 with a contact point 29 adapted for engagement with the contact member 24 heretofore mentioned.

The device operates in the following manner:

Assuming that the device is mounted on an electric iron, upon the predetermined temperature being reached, the ex ansible members 14 under the influence o the heat, expand longitudinally and the total expansion 100 of the members is communicated to'the projection or hump 9.8 on the plate 27, wl11ch 1s by reason of said pressure buckled or dlstorted, causing the contact point 29 suddenly to disengage the contact 24 and break the circuit through the conductors 25 and 28 at this point. Owing to the nature of the plate 27,

this contact is broken with a sharp, uick action, which reduces the sparking at-t 1e point of breaking of the circuit, and upon the cooling of the expansible elements the action of the plate to close the circuit is likewise rapid, thus preventing arcing or sparking durlng the closing operation.

By reason of the expansible elements being held between the stationary adjusting screw 8 and the rocking levers 16 and 17, the expansion of each element is transferred and the total expansion of all of the expansible elements is transmitted to the plate 27, thus giving suflicient power at this point to buckle the plate 27 for the purpose intended.

In Fig. .2 is a shown a condenser A, which may, if desired, be used in the circuit for the purpose of reducing arcing at the point of opening and closing of the circuit From the foregoing it is apparent that the present invention provides a new and improved thermostatic circuit breaker in which great power is derived from the expansion of the elements, and, at the same time, the' construction permits of the use of solid expansible elements rather than those of the laminated type, and also departs from the common structure of thermostatic devices, that is, lateral flexure of the expansible elements.

While in the present instance three expansible elements have been shown, i. e., the elements 14, it is obvious that this number may be increased or decreased as desired without departing from the spirit of the invention.

What is claimed is:

1. A thermostatic device, comprising two spaced and apertured frame members, each provided with an arm at one end, three expansible members mounted in the openings of the frame members with their ends projecting through said openings, an adjusting screw carried by the arm of the upper frame member and engaging the upper end of the first expansible members, a T-shaped lever pivoted to the lower frame member and engaging the lower ends of the first and second expansible member, a T-shaped lever pivotedto the upper frame member and engaging the upper ends of the second and third expansible members, a bracket secured to the lower frame member and having an insulating member secured thereto and resting on the post mounted in theinsulating member and arm of the lower frame member, a binding havin a contact member at its end, and a deforma le plate having one end secured to the lower frame member and having a contact members, meansfor connecting the said ele ments, whereb the multiplied expansion of the said mem rs will be transmitted to a given point, a bracket carried by the lower frame member and carrying a member of insulating material, a binding post mounted in the member of insulating material and having a contact at its end, and a spring metal plate secured to said bracket and having at its free end on its lower face a contact 1 point engaging the contact of the binding post and intermediate its ends a non-developable stamped surface on its upperface engaging the lower end of one of the expansible elements.

having a contact on its under face at the free endengaging the contact of the binding post and intermediate of its ends a non-developable stamped surface on its upper face whereby it may be buckled, and means forbuckling said plate to disengage its contact from the contact of the binding post, said means comprising a plurality of longitudinally expansible elements one of which engages the non-developable surface and the members being so connected as to exert their combined expansion on said non-developable surface.

4. In a control mechanism for an electrically heated device, the combination with a heat responsive member having a portion thereof free to-move in response to variations in temperature, of a snapswitch comprising a thin, plane plate having one end secured and the other free to move and carrying'a contact, the secured end having a distortable portion, and means operated upon movement of the free portion of said heat responsive a 115 device, comprising v v .90 3. In a thermostatic device, a binding 0st having a contact at its end, a spring p ate concavo-convex' section of said switch and 6. In a control mechanism for an electrically heated device, the combination of a thermostatic element having a portion thereof movable in response to variations in temperature, a metallic element having a concavo-convex portion and a plane portion pro vided with a contact for closing the electric circuit, and means movable by the thermostatic element for exerting pressure upon the convex face of the concavo-convex portion of said metallic element to efiect a reversal of the concavo-convex portion of said metallic element and thereby effect quick movement of said contact to open the circuit.

7. In a control mechanism for an electrically heated device, the combination of a snap switch comprising a thin metallic member having one end fixed and provided with a concavo-convex section the other end being freely movable and having a contact, said switch being movable on the application of pressure upon the convex side of said concavo-convex section to effect a quick movement of said contact and break the circuit of the device and movable on the release of pressure upon the convex side of said concavo-convex section toeffect a quick movement of said contact to close the circuit and heat responsive means having a portion t ereof movable in response to variations in temperature to exert pressure upon the convex face of said concavo-convex section or to release the pressure thereon.

8. In a control mechanism for an electrically heated device, the combination of a snap switch comprising a thin metallic member provided with plane and resilient dented portions reversible upon the application of or removal of pressure thereon and having a contact carried by said plane portion and adapted for quick movement upon the application of pressure to or removal of pressure from the dented portion to move the contact and open or close the electric circuit, and heat responsive means for exerting pressure upon the dented portion of said member or for releasing the pressure thereon.

9. In a control mechanism for an electrically heated device, a controlling element comprising a spring plate having a free operating extremity and a tensioned area causing the assumption by said plate of one of two positions of said operating extremity, means for supporting the plate in-the region of its tensioned area in a substantially fixed position leaving said operating extremity free for movement, and a heat-responsive operating member for exercising pressure on said Lensioned area, causing a quick snap into and maintenance of said plate in the second of its two positions for the duration of the pressure.

10. In a control mechanism for an electrically heated device, a snap switch comprising a thin metallic member provided with a distortable portion and having one end thereof fixed and the opposite contactor end free for movement, a support for said member located between the distortable portion and said free end, and heat-responsive means for exerting pressure upon the distortable portion to shift the member in reference to said support and impart quick movement to the free contactor end into a circuit-opening position. 11. A switch comprising a plate of spring metal, a dent in said plate, means for supporting said plate at points upon opposite sides of the dent, an electrical contact carried by a free extremity of the plate, and means operable against the dent thus to dis tort the plate in reference to the supporting points and displace the free extremity.

HILTON IRA JONES. 

